Air filter



FIG. 1 is a perspective view of an air filter showing our new design, configured vertically;

FIG. 2 is a front elevation view thereof;

FIG. 3 is a rear elevation view thereof;

FIG. 4 is a right side elevation view thereof;

FIG. 5 is a left side elevation view thereof;

FIG. 6 is a top plan view thereof; and,

FIG. 7 is a bottom plan view thereof.

The features shown in the dot dash lines depict environmental subject matter only and form no part of the claimed design. 

CLAIM We claim the ornamental design for an air filter, as shown and described. 